Implements an automatic local download fallback, similar to SSH
(cc @roblourens). If the initial download results in an error, either
in making the request or a 5xx, it'll try to fall back to making the
request locally and streaming it over the tunnel.
This abstracts the request client behing a "SimpleHttp" trait which
either uses to the native reqwest or uses the 'delegated' mode over the
socket.
- Start separating a "standalone" CLI. This is a little awkward with clap-
derive, but I got it working. Detection of whether the CLI _is_
standalone is still todo.
- Remove the old ad-hoc update code for code-server, and use the update
service instead.
- Fix some of the "permission denied" errors people got while updating
before. We need to rename the old running binary, not just overwrite it.
Connor Peet